# THe Drake equation explored

Posted on Tue Jan 23rd, 2018 @ 9:39am by Commander Bertrand Cuprum

For those of you who were interested in the chance of life according to the Drake equation, here is a little reading on the topic.

The Drake Equation, as it was stated in 1967 goes

R, the average rate of star formations, in our galaxy,
fp, the fraction of formed stars that have planets,
ne for stars that have planets, the average number of planets that can potentially support life,
fl, the fraction of those planets that actually develop life,
fi, the fraction of planets bearing life on which intelligent, civilized life, has developed,
fc, the fraction of these civilizations that have developed communications, i.e., technologies that release detectable signs into space, and
L, the length of time over which such civilizations release detectable signals,

Number = R*fp*ne*fl*fi*fc*L

When we come to look at your sample of 1900 stars it starts out looking REALLY promising.

R = 1900 (for the region we are considering.)
fp = 1 (Current theory is this is almost 1, where every start produces planetary bodies. Lets be generous and agree.)
ne = 0.4 (as of November 2013)
fl = 0.5 (No actual data exists. We have found many earth like planets but there is no way of telling if life has developed there. the only worlds we can study is Earth which has a probability of 1. Mars and Venus, just outside have a probability of 0. So I am going to arbitrarily choose 0.5, though potentially much higher.)
fi = 0.5 (as above, though we don't really have a description of Intelligent yet.)
fc = 0.5 (as above, though probably much lower.)
L = 3 Billion (Originally hypothesized as being 420, based on civilizations like Rome. I am being far more generous)

So our figure comes out to 1900*1*.4*.5*.5*.5*.5*3*10(9) or 142.5 billion. Wait... 142billion life forms on only 1900 planets? Anyone else seeing problems here yet?

SO instead let us REVISE the equation
N being the number of Stars in the region that exist for longer than the 4 Billion years it takes to develop intelligent life. This changes R, but we will expand our area till we have at least 1900 planets available (a much larger area but our values are unchanged).
L to be the Fraction of a planets history in which it can produce signals. Our 3 billion drops to about .4, making our total now 57. We also have to allow for the period of time a civilization can HEAR the signals from another. For us this is less than .0000001, but for a the sake of completeness, lets allow .4, taking our total to 22.8 out of 1900.

This still does not factor in things like distance traveled by the signal.

For some real application:
Let us assume that out there is ET sending a phone number so we can call him direct at the speed of light. Given we have to allow time for the signal and return of any message, no individual would be likely to be able to wait more than 80 years for a reply to anything they sent, even as a very young child. That gives us a maximum range of 40 light years for meaningful communication.

We have been searching for ET signals since the 60s (nearly 8 years now) and have been generating hearable signals since 1900s (close to 120 years). That means it is unlikely there is any life within 0-30 light years of us. There may still be slim hope for a most distant civilization, but given there are only about 1400 star systems inside a 50 ly radius of earth (16 civilizations over the whole area), and we have ruled out the most close systems, our probability drops significantly. at our most generous, the chance of life is less than .007%

Category: Out of Character
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